DP Chemistry (last assessment 2024)

Test builder »

Question 23M.3.SL.TZ1.9

Select a Test
Date May 2023 Marks available [Maximum mark: 9] Reference code 23M.3.SL.TZ1.9
Level SL Paper 3 Time zone TZ1
Command term Deduce, Explain, Identify, Outline, Suggest Question number 9 Adapted from N/A
9.
[Maximum mark: 9]
23M.3.SL.TZ1.9

Energy is often converted into more usable forms.

(a)

The efficiency of a nuclear power plant is approximately 33 %.

(a.i)

Outline the meaning of the above statement in terms of energy conversion.

[1]

Markscheme

33 % of energy input/released «in fission» is converted to electricity ✓

 

Do not accept generalizations, such as “Only produces 33 % useful energy.”

(a.ii)

The fusion of two deuterium nuclei, H12 , can occur in two ways:

H12+H12→X+n01

H12+H12→Y+p11

Deduce the nuclear symbols for X and Y using the correct notation.

 

X:  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  . . . . . . . 

 
Y:  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  . . . . . . .

[1]

Markscheme

X H23e AND Y H13 ✓

(a.iii)

Explain which fusion reaction of deuterium releases more energy. Use section 36 of the data booklet.

[1]

Markscheme

2nd/Y/H13 AND formation H13 has greater increase in binding energy «per nucleon than formation H23e ✓


Accept 2nd/Y/H13 AND “It is higher on the binding energy curve”.

(a.iv)

Suggest why the specific energy of deuterium in fusion is higher than that of uranium-235 in fission, yet the energy density of uranium is significantly greater than that of deuterium. Use section 1 of the data booklet.

[4]

Markscheme

deuterium contains more atoms per unit mass «than uranium as it has a lower molar mass» ✓

fusion releases more energy per atom than fission ✓

«solid» uranium «much» more dense «than deuterium»
OR
uranium contains more atoms per unit volume «than deuterium, as it is a solid» ✓

increase in density has a greater effect than fusion releasing more energy than fission ✓

(b)

Catalytic reforming and cracking can produce more efficient fuel.

(b.i)

Deduce the equation for the conversion of heptane to methylbenzene.

[1]

Markscheme

C7H16 → C6H5CH3 + 4H2 ✓

 

Accept C7H8 for C6H5CH3.

(b.ii)

Identify two products that can be formed from cracking heptane.

[1]

Markscheme

any alkane AND alkene where total sum of C=7 and H=16;
e.g. C5H12 AND C2H4 ✓